小程序支付-即速应用

1.开通微信支付和微信商户号

这个过程就和开通服务号的微信支付过程一样，没有什么可以说的。
小程序

2.获得用户的openid

首页我们需要在小程序的客户端js中获取当前用户的openid,通过调用wx.login方法可以得到用户的code,然后开发者服务器使用登录凭证 code 获取 openid。

wx.login({      success: function(res) {        if (res.code) {          //发起网络请求          wx.request({            url: 'https://qifeng.site/onLogin',            method: 'POST',            data: {              code: res.code            },            success: function(res) {                var openid = res.data.openid;            },            fail: function(err) {                console.log(err)            }          })        } else {          console.log('获取用户登录态失败！' + res.errMsg)        }      }    });

3.获取prepay_id和支付签名验证paySign

这一步的过程就和服务号里的微信支付过程一样，分为客户端和服务器端
首先来看一下客户端js
在服务号里，我们是通过如下的代码来调起支付功能

///在小程序里，我们是通过wx.requestPayment方法来调起支付功能，当然在这之前，我们先要获取prepay_id。wx.request({     url: 'https://qifeng.site/service/getPay',      method: 'POST',     data: {       pkg:pkg,  /*订单号*/       total_fee:total_fee,   /*订单金额*/       nonceStr:nonceStr       openid:openid     },     header: {         'content-type': 'application/json'     },     success: function(res) {        wx.requestPayment({           'timeStamp': '',//即当前的时间           'nonceStr': '',//随机字符串，长度为32个字符以下。           'package': '',//统一下单接口返回的 prepay_id 参数值，提交格式如：prepay_id=*           'signType': 'MD5',//签名算法，暂支持 MD5           'paySign': '',//签名,具体签名方案参见[小程序支付接口文档;](https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=7_7&index=3)           'success':function(res){//调用支付成功           },           'fail':function(res){//           },           complete(res){//接口调用结束的回调函数（调用成功、失败都会执行）           }        })     },     fail: function(err) {         console.log(err)     } })//在服务号里，通过如下的代码来调起支付功能function jsApiCall() {      WeixinJSBridge.invoke(          'getBrandWCPayRequest',          {             "appId":"",     //公众号名称，由商户传入                  "timeStamp":"",         //时间戳，自1970年以来的秒数                  "nonceStr":"", //随机串                  "package":"prepay_id=%=prepay_id%",                  "signType":"MD5",         //微信签名方式：                  "paySign":"%=_paySignjs%" //微信签名          },          function(res){              WeixinJSBridge.log(res.err_msg);              if( res.err_msg =="get_brand_wcpay_request:ok"){                  alert("支付成功!");              }else{                  alert("支付失败!");              }          }      );  }

那在服务器端主要要实现的是prepay_id的获取和签名paySign

var bookingNo = req.param("bookingNo"); var total_fee = req.param("total_fee"); var openid = req.param("openid"); var body = "费用说明"; var url = "https://api.mch.weixin.qq.com/pay/unifiedorder"; var formData = "xml"; formData += "appidappid/appid"; //appid formData += "attachtest/attach"; formData += "body" + body + "/body"; formData += "mch_idmch_id/mch_id"; //商户号 formData += "nonce_strnonce_str/nonce_str"; formData += "notify_urlnotify_url/notify_url"; formData += "openid" + openid + "/openid"; formData += "out_trade_no" + bookingNo + "/out_trade_no"; formData += "spbill_create_ipspbill_create_ip/spbill_create_ip"; formData += "total_fee" + total_fee + "/total_fee"; formData += "trade_typeJSAPI/trade_type"; formData += "sign" + paysignjsapi(appid, attach, body, mch_id, nonce_str, notify_url, openid, bookingNo, spbill_create_ip, total_fee, 'JSAPI') + "/sign"; formData += "/xml"; request({     url: url,     method: 'POST',     body: formData }, function(err, response, body) {     if(!err && response.statusCode == 200) {         var prepay_id = getXMLNodeValue('prepay_id', body.toString("utf-8"));         var tmp = prepay_id.split('[');         var tmp1 = tmp[2].split(']');         //签名         var _paySignjs = paysignjs(appid, mch_id, 'prepay_id=' + tmp1[0], 'MD5',timeStamp);         var o = {             prepay_id: tmp1[0],             _paySignjs: _paySignjs         }         res.send(o);     } });////用到的一些其他的方法function paysignjs(appid, nonceStr, package, signType, timeStamp) {    var ret = {        appId: appid,        nonceStr: nonceStr,        package: package,        signType: signType,        timeStamp: timeStamp    };    var string = raw1(ret);    string = string + '&key='+key;    console.log(string);    var crypto = require('crypto');    return crypto.createHash('md5').update(string, 'utf8').digest('hex');};function raw1(args) {    var keys = Object.keys(args);    keys = keys.sort()    var newArgs = {};    keys.forEach(function(key) {        newArgs[key] = args[key];    });    var string = '';    for(var k in newArgs) {        string += '&' + k + '=' + newArgs[k];    }    string = string.substr(1);    return string;};function paysignjsapi(appid, attach, body, mch_id, nonce_str, notify_url, openid, out_trade_no, spbill_create_ip, total_fee, trade_type) {    var ret = {        appid: appid,        attach: attach,        body: body,        mch_id: mch_id,        nonce_str: nonce_str,        notify_url: notify_url,        openid: openid,        out_trade_no: out_trade_no,        spbill_create_ip: spbill_create_ip,        total_fee: total_fee,        trade_type: trade_type    };    var string = raw(ret);    string = string + '&key='+key;    var crypto = require('crypto');    return crypto.createHash('md5').update(string, 'utf8').digest('hex');};function raw(args) {    var keys = Object.keys(args);    keys = keys.sort()    var newArgs = {};    keys.forEach(function(key) {        newArgs[key.toLowerCase()] = args[key];    });    var string = '';    for(var k in newArgs) {        string += '&' + k + '=' + newArgs[k];    }    string = string.substr(1);    return string;};function getXMLNodeValue(node_name, xml) {    var tmp = xml.split("" + node_name + "");    var _tmp = tmp[1].split("/" + node_name + "");    return _tmp[0];}